The decision to award it to KDPW (short for Krajowy Depozyt Papierów Wartościowych) was issued by the country’s supervision authority KNF on 3 March.
The authorisation under CSDR is effectively a passport allowing the holder to provide CSD services, such as recording, safe keeping and trade settlement of financial instruments, in countries across the EU. For the EU, this serves to transform CSDs from national de-facto monopolies to open-market competitors, for the benefit of market participants, and to harmonise settlement rules.

Now around 20

To see the list of CSDs authorised under CSDR, find here the official CSD register held by the European Securities and Markets Authority (ESMA). Before updating with KDPW, it lists 19 licensed bodies – most of them national but also including Euroclear’s international CSD.
The European Central Securities Depositories Association (ECSDA), too, publishes a CSD list which is often updated quicker. Find it here.